When we sleep, our immune system is busy producing protective, infection-fighting substances that help protect us from bacteria and viruses. A lack of sleep means that we’re unable to build up this protection and our bodies will take longer to recover from illness. This in itself is bad enough, but sleep deprivation can lead to far more serious health issues.
Studies have shown that depriving healthy volunteers of sleep can cause increased stress, increased blood pressure, impaired control of blood glucose and increased inflammation. And this is after only a short period of time! Long-term sleep disorders are associated with a variety of diseases and health issues. Recent research has also suggested that adjusting sleep to a more healthy pattern can reduce the risk of developing a disease or even lessen the severity of an on-going disease, thus showing the vital importance of a good night’s rest.
We’ve discussed in other articles how a lack of sleep can cause diabetes and mood disorders, such as depression. But there are other health issues caused and exacerbated by sleep deprivation.
One example is the correlation between poor sleep and cardiovascular disease and stroke. People who have existing hypertension (chronic elevation of blood pressure) and miss even a single night’s sleep can end up with elevated blood pressure the following day, which raises the risks of cardiovascular issues. There is also growing evidence of a link between heart disease and obstructive sleep apnea. Those suffering from sleep apnea typically wake up multiple times during the night as a result of their airways closing off for brief periods. As they wake up, they also experience brief surges in blood pressure. Over time this can lead to hypertension, which is, as we’ve already discussed, a major risk factor for cardiovascular disease.
Poor sleep has also been linked to weight gain. Sleep deprivation is now being seen as a potential risk factor for obesity along with lack of exercise and overeating. Studies show that those who sleep less than six hours per night are much more likely to have a high BMI (body mass index) and are around 30% more likely to become obese. There is a clear link between sleep and the peptides that regulate our appetite. Ghrelin stimulates hunger, whilst leptin suppresses it and shortened sleep time has been proven to be linked to decreases in leptin and increases in ghrelin. Sleep loss also seems to up our cravings for high fat, high carbohydrate foods. In addition poor sleep is also associated with increases in the secretion of insulin following a meal. Insulin regulates glucose processing and promotes fat storage and higher levels of insulin are also associated with weight gain.
When we look at all the health risks from a lack of sleep, it’s perhaps not surprising that studies have revealed that sleeping five hours or less increases mortality risk from all causes by around 15%. So sleep really is vital to keep us fit and healthy.
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